Study of the photoresponse of ITO/SiO2/Si/SiO2/Al MIS capacitor structures

In this work, we report on the photoresponse properties of metal-insulator-semiconductor (MIS) devices using a SiO2/Si/SiO2 multilayer (ML) as active I-layer and deposited on p-type and n-type Si substrates. The effect of a post-thermal annealing of the SiO2/Si/SiO2 ML was analyzed. Thermally annealed (TA)-MLs did not show any photoresponse, while devices with as-deposited (AD)-SiO2/Si/SiO2 ML (without TA) exhibit a strong photoresponse. Current vs voltage curves were performed in dark and under illumination using white, blue, green, yellow, and red LEDs; the (white) light/dark current ratio obtained at 0V is about 8.54E3 and 7.95E3 for n-type and p-type substrates, respectively. Moreover, AD-ML devices on n-type Si substrate exhibit the best results with a spectral response and external quantum efficiency values (at 0V) of 58.28 mA/W and 13.58% at 532 nm, respectively.